1. Field of the Invention
This invention relates to an apparatus for an endothermic reaction of a gas represented by steam reforming in which the heat of combustion generated in the space for producing flue gas of the smallest possible volume is imparted to the reactants in the reactor for such reaction through the wall of the reactor as a heat flux of high density.
2. Description of the Prior Art
In order that the heat of combustion generated in the space or room for producing flue gas is imparted to the reactants or raw material gas through the wall of the reactor as a heat flux of high density, it is a common practice for gaseous endothermic reaction apparatus such as steam reforming apparatus to maintain the temperature of the flue gas in the space for producing flue gas as high as possible, to maximize the thickness of the flue gas layer, to maximize the reflectance of heat rays at the inner surface of the combustion furnace defining the space for producing flue gas, etc.
Even if these means are applied collectively, the heat flux penetrating through the wall of the reactor is about 150,000 Kcal/m.sup.2 .multidot.hr at the highest in an industrial apparatus.
Increased thickness of the flue gas layer will cause the volume of the combustion furnace to be inevitably large, so that the resulting whole apparatus will necessarily be increased in size even if the volume of the reactor itself which is housed in and heated by the combustion furnace is small.
It has been practiced to reduce the volume of the combustion furnace by placing in the combustion furnace a refractory solid material having much larger emissivity than gases at high temperatures and heating the solid material with the flue gas to maintain it at high temperatures so as to make it emit heat rays from the solid material to the wall of the reactor. Further, it has also been proposed for the same purpose to make use of the heat of combustion generated by the catalytic oxidation of fuel.